Pittsburgh hand tool

ABSTRACT

Disclosed is a tool useful for fabricating sheet metal ductwork, the tool comprises a handle portion extending from an end of which are first and second prongs, the first prong extending from and in substantially the same plane as the handle portion, the second prong extending outwardly from the handle at a obtuse angle and spaced apart and opposite from the first prong; the second prong having an arcuate tip end that is curved radially at an acute angle toward the direction of the first prong but extending just beyond it.

FIELD OF THE DISCLOSURE

The disclosure relates to a hand tool useful in the fabrication of sheet metal ductwork in the HVAC industry. In one embodiment, the tool of the disclosure is categorizable in the art as a Pittsburgh Lock Opening Tool which is used to open longitudinal seams on sheet metal ductwork.

BACKGROUND

Metal ductwork is often formed of connected sections, commonly having a rectilinear cross-section. A Pittsburgh Lock is known to be a type of corner joint between two pieces of sheet metal. It is made by a particular type of folding of the sheet metal edges to create a desired profile which interlocks to join two pieces together. Such a joint is typified by longitudinal seam in the ductwork. For purposes of ductwork fabrication, repair and/or replacement, this longitudinal seam needs to be opened. While various methods of doing so are known, an improvement is nonetheless needed in the related tooling. Such known tools typically have, at the working end, flat sides and sharp angles, including right angles, which shapes can create difficulties in getting the tool to gain entry to and properly mate with the Pittsburgh Lock, requiring awkward and time-consuming manipulations. Such known tools also require more extensive manufacture given the multiplicity of sharp angles needed and flat planes required, Thus, there is a need for a hand tool that can be more simply made and that allows for easier entry to and mating with a Pittsburgh Lock, and that will better support the longitudinal seam as it is being opened, and which will prevent opening of the seam beyond a certain amount, e.g. will prevent opening of the seam by more than a 90° angle. In addition, there is a need for a way to quickly store the tool in the work area when it is not being used, yet for it still to be easily available when needed.

SUMMARY OF THE DISCLOSURE

The disclosure is directed to a tool comprising an elongate handle portion having a first end and a second end, wherein the first end has a first prong and a second prong. The first prong extends outwardly from the handle portion and in substantially the same plane as the handle portion, e.g., substantially collinearly with the handle portion. The second prong extends outwardly and away from the handle portion at an obtuse angle. The second prong is located opposite from, and in spaced relation to, the first prong. The second prong ends in a tip portion. The tip portion extends beyond the first prong and is curved radially, at an acute angle, toward the plane of the first prong. In one aspect, the obtuse angle and rounded acute angle tip of the tool of the disclosure provides for easier entry to and mating with a Pittsburgh Lock than tools heretofore known. The tool of the disclosure is also more easily manufactured, requiring less bending during fabrication. This simpler design also requires less material, such as steel, to make the tool, leading to a reduction is cost; and the overall shape of the tool is more ergonomic for the user.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an embodiment of a tool of the disclosure.

FIG. 2 is a plan view of the underside of the tool of FIG. 1.

FIG. 3 is an enlarged side view of the second prong and tip portion of the tool of FIG. 1

DETAILED DESCRIPTION

The description herein is made with reference to the Figures. This is for purposes of convenience only and is not restrictive or limiting to the scope of the disclosure and the practice thereof.

Referring to FIG. 1, depicted thereat is a cross-sectional view of an embodiment of the tool of the disclosure. As shown in this particular embodiment, tool 10 comprised of elongated handle portion 17. In one practice, elongated handle portion 17 is a rigid, flat, and substantially planar, substantially rectangular handle portion comprised of, without limitation, metal (e.g. cold-rolled steel), plastic, glass-filled nylon and like materials as known in the art for sheet metal tooling. In the embodiment depicted at FIG. 1, the handle portion 17 extends from a first end, generally shown at 12, to a second end, generally shown at 11. The first end 12 comprises two prongs, 13 and 14. First prong 13 extends in an outward direction from handle portion 17 and lies in substantially the same plane as handle portion 17. In the embodiment shown in FIG. 1, first prong 13 is substantially contiguous with handle portion 17 and is in the same horizontal plane.

As shown in FIGS. 1 and 3, second prong 14 comprises a flat, substantially straight portion 15 and a rounded tip portion 16. As shown in FIG. 1, straight portion 15 extends outwardly from handle portion 17 by an obtuse angle α. In one practice, angle α is between about 125° to about 135°; preferably, between about 128° and about 130°, e.g. 129°. Straight portion 15 has a bend radius (R) of between about 0.180 and 0.195 inches; preferably about 0.190 inches, including e.g. 0.187 inches. Second prong 15 ends in tip portion 16, which tip portion is curved radially at acute angle β toward the plane in which the first prong 13 lies. In one embodiment, acute angle β is between about 25° and 40°; preferably about 30°. Tip portion 16 has an inner bend radius (R′) of between about 0.035 to about 0.045 inches; preferably 0.40 inches. Tip portion 16 has tip face 19 at the end thereof, which tip face 19 can be flat (as depicted in FIGS. 1-3), beveled or sharpened.

Second prong 14 is located opposite first prong 13 and is in spaced relation to first prong 13 such that the first and second prongs 13 and 14 are configured in relation to each other to permit them to cooperatively engage a seam on a piece of sheet metal duct, e.g. a longitudinal seam on a Pittsburgh Lock, in order to open same. In such a configuration, the first prong 13 acts as a fulcrum for opening the seam and is further dimensioned to support the seam as it is being opened and to additionally act to limit the degree to which the seam can be opened, e.g. to prevent opening the seam beyond a 90° angle. In one practice, straight portion 15 curves outwardly from the handle portion at an angle α of 129° through a bend radius R of 0.187 inches; and tip portion 16 curves at an angle β of 30° through a bend radius R′ of 0.040 inches. Preferably, as shown in FIGS. 1-3, tip portion 16 extends just beyond the end portion 13 a of first prong 13, and the ratio of the length (d′) of tip portion 16 to the distance (d) between the top of tip portion 16 and the upper surface of first prong 13 is about 0.4 to 0.350, preferably 0.375. Thus for example, if d is 0.750 inches, d′ is 0.375 inches. The first and second prongs can be separate components that are fixedly secured to handle portion, or they can be each or both made integral with the handle portion to form a unitary tool. Although not bound by particular dimensions, in one embodiment, the handle portion is approximately 7 inches long (L) and approximately 1.125 inches wide (W), with d being 0.750 inches and d′ being 0.375 inches.

Handle portion 17 can comprise one or more hang holes, e.g. hang hole 18 located proximate second end 11 of handle portion 17 as shown in FIG. 2. The handle portion can further be magnetized or comprise a magnetized portion, such as a magnet 20 inserted into handle portion 17 by way of a depression in the handle into which a magnet is inserted or an opening into which a magnet is fitted, the magnet being of a type sufficient to permit the tool to be stored and accessed at the work site by, e.g. magnetically adhering the tool to the sheet metal duct work under fabrication or to other conveniently local metal objects, while other tasks are being performed.

In the embodiment illustrated in FIGS. 1-3, tool 10 is formed from a single unitary flat piece of rectangular metal, e.g. cold rolled steel, that is bent back upon itself at juncture 17 c to form a layered structure, having a bottom layer 17 a and a top layer 17 b, both of which layers together comprise the handle portion 17. The bottom and top layers 17 a and 17 b can be spot welded as needed to further secure the two together. In the practice shown, first prong 13 is an extension of bottom layer 17 a whereas second prong 14 is an extension of top layer 17 b which is bent at obtuse angle α which is bent again back upon itself at acute angle β to form tip portion 16 which extends just beyond the first prong. Other configurations, including use of multiple components for the handle and first and second prongs fitted and secured together to form the tool are within the scope of the disclosure.

The preceding description is exemplary only and is not limiting to the scope of the disclosure. 

What is claimed is:
 1. A tool comprising: a elongate handle portion having a first end and a second end, the first end having first and second prongs, the first prong extending outwardly from and in substantially the same plane as the handle portion, the second prong extending outwardly and away from the handle portion at an obtuse angle, the second prong located opposite from and in spaced relation to the first prong, the second prong ending in a tip portion that extends beyond the first prong, the tip portion being curved radially at an acute angle toward the plane of the first prong.
 2. The tool of claim 1 wherein the handle portion is flat and substantially planar.
 3. The tool of claim 2 wherein the first and second prongs are flat and substantially planar.
 4. The tool of claim 1 wherein the obtuse angle is between about 125° to about 135°.
 5. The tool of claim 4 wherein the obtuse angle is between about 128° and about 130°.
 6. The tool of claim 1 wherein the acute angle is between about 25° and 40°.
 7. The tool of claim 6 wherein the acute angle is about 30°.
 8. The tool of claim 1 wherein the handle portion is formed from a unitary piece bent back upon itself.
 9. The tool of claim 1 wherein the first and second prongs are integrally formed from the handle portion.
 10. The tool of claim 1 wherein the handle portion further comprises a magnetized portion.
 11. The tool of claim 10 wherein the magnetized portion comprises a magnet inserted into the handle portion.
 12. The tool of claim 1 further comprising a hang hole proximate the second end of the handle portion. 